Purlin Roof Framing

The width of metal panels will determine the rafter spacing.

Purlin roof framing. First the purlins support the roof. In traditional timber framing there are three basic types of purlin. In architecture structural engineering or building a purlin or historically purline purloyne purling perling is any longitudinal horizontal structural member in a roof except a type of framing with what is called a crown plate. Metal building roof purlins provide three structural functions.

Thirdly purlins add additional support between the spans of the individual framing bays. The metal roof purlins spacing must be done correctly within narrow tolerances. Purlins are supported either by rafters or the walls of the building. Welded together they can be used as columns braces and ties.

There is a chance of damaging roofing sheets if you are failed to do so. Cee purlins are secondary steel framing members most commonly used as roof purlins wall girts and header jamb and sill for windows and doors on metal buildings. The purpose of purlins. The roof support system is a ridgepole and either rafters which run perpendicular from the top of the walls to the ridge or purlins which run parallel to the ridge.

A common arrangement is a rafter and purlin system which combines purlins and rafters. Secondly purlins tie the rafters together stabilizing and strengthening the structure s rigid framing. The purlins of a roof support the weight of the roof deck. The purlin are ultimately used to fasten the roof steel providing a diaphragm effect along with the siding when properly engineered and installed.

The shape of cee purlins does not allow end lapping they are butted together. They are most commonly used in metal buildings though they sometimes replace closely spaced rafters in wood frame structures. Roof hugger retrofit sub purlins are zee shaped structural members that are typically 10 to 12 feet in length. They are made from 16 ga 0 060 min 50 ksi structural grade g 90 galvanized steel and specifically notched to fit over the ribs of the existing metal roof panels.

Purlin plate principal purlin and common purlin.